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(No Model.) 2 Sheets-Sheet 1.

C. D. ROGERS.

DIE FOB. SWAGING THE POINTS AND THREADS 0P WOOD scRnws.

No; 375,098. Patented Dec. 20, 1887.

m5- Model.) 2 SheetsSheet 2. C. D. ROGERS.

DIE FOR swAGlNG THE POINTS AND THREADS 0? W001) SCREWS. N0. 375,098.

Patented Dec. 20, 1887.

IEII BI INVEN TCIR RG72 arid .sjD j fa qera.

WITNEES ES.

UNITED STATES PATENT OFFICE.

CHARLES D. ROGERS, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO THE AMERICANSCREW COMPANY, OF SAME PLACE.

DIE FOR SWAGING THE POINTS AND THREADS OF WOOD-SCREWS.

SPECIFICATION forming part of Letters Patent No. 375,098, dated December20, 1887.

Application filed July 7, 1887. Serial No. 243,671. (No model.)

To aZZ whom it may concern.-

Be it known that 1, CHARLES D. Roenns, a citizen of the United States,residing at Providence, in the county of Providence and State of RhodeIsland, have invented certain new and useful Improvements in Methods ofForming and Screw-Threading the Points of WVood- Screws; and I do herebydeclare the following to be afull, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same, referencebeing had to theaccompanying drawings, and to letters or figures of reference markedthereon, which form a part of this specification.

This invention relates to an improved method of shaping andscrew-threading the points of wood-screws; and it consists in passin gthe blank between dies, the action of which is to first roll or impressa partly-formed thread into the body of the shank, and at the same timeroll the rough point of the blank into shape preparatory to beingthreaded,the continued action of the said dies completely forming thescrew-thread both on the shank and pointed portions of the screw.

It also consists in the novel construction of the dies and mechanism foroperating them.

Wood-screws as commonly screw-threaded are first passed throughapointingmechanism which gives a proper form to the point of the blank. Thisoperation becomes necessary when the blanks are severed from the rod byshearing or pinching, from the fact that more or less of a burr or finis left on the point. It is evident that the employment of such pointingmechanism,when in a separate machine, including the attendance of anoperator, necessarily increases the cost of manufacture. Moreover, whererolling dies are provided with thread-forming ribs adapted to thread thepoint of a screw (not previously prepared) coincident with the formingof the thread on the shank of the screw, the reduction of the metal ofthe pointed end and its consequent elongation produces additionalstrains upon the dies, the same being due to the opposed action of themetal of the screw in flowing both'laterally and longitudinally at thesame time. The screws thus produced are found to be inferior, owing tothe fact that the thread on the point is rough, in some instances beingonly partly finished, while in others the threads are nearly or quitedetached at the root from the core, due to the cause stated,wherein, informing the thread, the unyielding ribs and grooves of the dies retainthe stock impressed therein, but the end of the screw while being rolledinto shape is elongated, thereby causing the metal to quarrel, as it maybe termed.

The object of my improvements is to overcome these disadvantages andproduce a superior wood-screw at a reduced cost. These results Iattainby the use of peculiar dies,each of which for a portion of its length atthe lower or point-forming portion (and at the entering end thereof)being without grooves and having a form adapted to roll and elongate thepointed end of the blank to a uniform shape. This plain or ungroovedportion merges into acorrespondingly-shaped portion of the die, intowhich obliquely-arranged grooves uniting with the main threading-groovesare cut, adapted to roll a thread on the screw-point while thescrew-shank is being completely threaded.

The dies are provided at the lower contiguous edges with an extension orcutter adapted to sever from the point of the screw any superfluousstock remaining after the thread is formed thereon. I

The shape of the thread forming ribs adapted to produce a solidscrew-thread raised from the surface of a screw-blank is shown andclaimed in an application for United States Letters Patent, filed by meMay 11, 1887, Serial No. 237,824.

In the annexed two sheets of drawings, Figure 1, Sheet 1, represents inelevation the working-face of one of a pair of dies constructedsubstantially according to my present invention. Fig. 2 is a transversesectional view, taken through a pair of said dies, corresponding to line0 0, Fig. 1. Figs. 3 and 4 are similar views taken through linesa: a;and a u of Fig. 1, respectively. Fig. 5 is a perspective view of aheaded screw-blank as roughly severed from a rod, as usual. Fig. 6 isasimilar view of the lower portion of a blank, showing fins formedthereon by the action of the cuttingofi' dies. Figs. 7,8, and 9represent perspective ICO views of the screwblank corresponding to theseveral stages in rolling the thread by the dies, at the lines 88, com,and are, respectively. Fig. 10 is a plan view of a machine having myimproved dies mounted therein and adapted to shape the point of ascrew-blank and to roll a screw-thread into the shank and point of theblank. Fig. 11 is a transverse sectional view taken on line .10 or ofFig. 10, viewed from the left. Fig. 12, Sheet 2, is a side elevation ofthe working-face of my improved die, its lower edge being divided intothree parts or seetionsviz., the first part being adapted to roll thepoint of the blank into proper form preparatory to being threaded andsimultaneously with the commencement of the threads on the body of theblank, the second section being constructed and adapted to roll thescrew-thread on the pointed portion of the screw, and the third sectionis composed of a knife or cutter adapted, in" conjunction with itsfellow die, to remove any superfluous stock from the tip of the point,which may have been produced during the rolling process. Fig. 13 is atransverse sectional view of a pair of mounted dies provided with suchcuttingedge, taken on line at m of Fig. 12; and Fig. 14: is aperspective View of a partly-finished screw, showing superfluous metalextending from the tip thereof as a result of shaping andscrew-threading the point.

In the drawings, A, Fig. 1, designates my improved die, made of steeland hardened. The working-face of the die is provided with a series ofobliquely-arranged thread-forming ribs, a, separated by grooves 21. Thelower edge portion of the die is beveled or angular, as at k. A portion,1), thereof, for about one third of the length of the die from theentering end (t*, is made smooth or ungrooved. This plain portion isadapted to reduce the roughened point of the blank, as p, Figs. 5 and6,into the proper symmetrical form necessary, and preparatory to thepoints engagement with the thread-forming portion 1) of the die about tobe described, the superfluous metal, if any, being forced out andextending from the pointof theblank. By means of thus shapiugthe pointsthe time and attendance necessary to produce the same result in anothermachine or operation are avoided. At the termination of the smoothportion b the ribs for forming the threads on the points commence. Thesethread-forming ribs and grooves are practically the prolongation ofthose which form the screw-threads on the body of the screw. It will beobserved, referring to Figs. 1 and 12, that a portion of the said ribsto and grooves 12 terminate along the upper edge of the plain orpoint-shaping porion 12.

Fi g. 10 represents in plan a machine adapted o produce a screw havingan automaticallyshaped and screw-threaded point, 12 Fig. 9. Said machinerepresents one of the dies A secured to the framing 13, while the otherdie is oppositely mounted in guides g and adapted to reciprocate backand forth in front of the stationary die, by means of a connecting-rod,d, crank c, and revolving shaft m. t indicates an inclined trough orrunway adapted to conduct blanks 8 Fig. 5, to the dies while the latterare normally separated, as at the end of the stroke. It is obvious thatthe dies may be mounted so that both are adapted to travel, in whichcase the screw will not advance but simply turn on its axis while beingsubmitted to the action of the dies.

The operation is as follows: A blank, 8", roughly pointed, as at pf,Figs. 5 and 6, and having a plain shank, s, terminating at its upper endin a head, it, (nicked, as at n, if desired,) is placed in a verticalposition at the left of the stationary die A. Now, by suitableconnections, the movable die is forced ahead toward the right, (seearrow-directiom) the dies being so adjusted in relation to each otherthat the blank is grasped between them at the same instant from oppositesides. The screw is carried along between the dies by the movable oneuntil it passes the rear end of the stationary die, when the screw dropsfrom them through an opening, 25, which conducts it to a receptaclebeneath. At the commencement of the operation the ribs a are forced intothe metal of the shank s, and as the rolling progresses to form thethread the lower portion, 12, of the dies at the same time transformsthe roughened point 1) into an elongated and symmetrical point,p, Fig.7. The further movement of the die as it carries the screw past the endof the plain portion 1) produces a continnation of the screw-thread 25from the shank to the end of the screw. The final action of the diesproduces a completely-threaded screw, E, substantially as represented inFig. 9.

In Figs. 12 and 13 the rear portion of the stationary die is provided onits under side with a short cutter, b, which, co-operating with thesharpened edge b of the movable die,

Fig. 13, serves to shear off any superfluous metal or burr, as b Fig.4-, from the lower end of the screw that may be produced during therolling process.

Having described my invention, I claim 1. Grooved dies for rolling thethreads on screws, each die having a portion of its working-face formedto first reduce and elongate the point portion of the screw-blank to asymmetrical shape by an ungrooved beveled surface, and then to roll ascrew-thread on said point, the latter thread being a continuation 'ofthat simultaneously produced on the body of the screw.

2. The combination, in a screw-threading machine, of two grooved dies,one of which may be stationary, for rolling the thread on screws, eachdie having a portion of its beveled working-face ungrooved to reduce thepoint of the screw-blank to a symmetrical shape, and then, by means ofribs and grooves formed in the succeeding portion of the said beveledsurface, to roll a sorewihread on the I sever superfluous metal from thetip of the 10 point of the screw. screw.

3. The combination of a pair of thread-forn1- In testimony whereof Ihave affixed my siging dies, each having a beveled portion of its naturein presence of two Witnesses. 5 Working-face longitudinally un groovedto first shape the point of the blank, and then, by CHARLES ROGERS meansof grooves formed in the continuation "Witnesses: of said ungrooveclportion, to roll a screw- CHARLES HANNIGAN, thread thereon, and acutting-edge adapted to G120. H. REMINGTON.

